[Hepatitis B and C infection in late repatriates]. / Hepatitis B und C bei Spätaussiedlern.

105 late repatriates returning to Germany mostly from Russia, Ukraine and Kazakhstan were tested for present or past viral hepatitis B and 97 of them also for hepatitis C. Anti-HBc was found in 20% (95%-CI: 12,3-31,6%) and Anti-HCV in 3% (95%-CI: 1,3-8,0%) of tested individuals. 5% of tested persons were positive by PCR for HBV-DNA or HCV-DNA and therefore probably source of infection forthese viruses. All PCR positive individuals were not aware of their infection. Prevalence of hepatitis B and C infection was significantly higher than in the general population of Germany. Testing for viral hepatitis Band C should be offered to all late repatriates returning from areas with elevated prevalence of parenterally transmitted viral hepatitis. Further monitoring of the prevalence of viral hepatitis should be done in this group.

[Tick-borne encephalitis and Lyme borreliosis. Spread of pathogens and risk of illness in a tick-borne encephalitis region]. / FSME und Lyme-Borreliose. Erregerverbreitung in Zecken und Erkrankungsrisiken in einem FSME-Risikogebiet.

A knowledge of the distribution of tick-borne agents and the related risks of contracting diseases are essential to ensure an appropriate response between hysteria and disregard, and to decide the appropriateness of vaccination. Illustrated by the German town of Lohr a. M. (Bavaria), the prevalence of TBE-virus and Borrelia burgdorferi in ticks was investigated and compared, and the respective risk of contracting disease from a bite assessed. Using the polymerase chain reaction (PCR), a total of 1657 ticks obtained from five different biotopes around Lohr were examined for the TBE-virus, and 408 ticks for Borrelia burgdorferi. The results were compared with earlier findings in other regions of Germany. The risk of contracting illness was estimated on the basis of transmission and manifestation rates, together with epidemiological data from the region. The prevalence of TBE-virus was 0.12% (95% CI: 0.05-0.44%) in the ticks investigated. This is comparable with that in 4 other regions rated as TBE-risk regions, but significantly lower than that in rated high-risk regions. Borrelia burgdorferi was detected in 14.9% (11.8-19.0%) of adult ticks, roughly twice the prevalence found in nymphs (7.2%, range 4.6-11.7%). On the basis of these prevalences, the risk of contracting meningitis/encephalitis from a tick bite is about 1:10,000, and the risk for Lyme Borreliosis is about 1:100, the latter requiring that the tick remains attached for at least 2-3 days.

Dystrophin and the dystrophin-associated glycoprotein, beta-dystroglycan, co-localize in photoreceptor synaptic complexes of the human retina.

Mutations in the gene encoding for dystrophin, a membrane-associated cytoskeletal protein of muscle and several non-muscle cells, are the cause of Duchenne muscular dystrophy and Becker muscular dystrophy. Patients suffering from Duchenne muscular dystrophy have recently been shown to display an abnormal b-wave of the electroretinogram, suggesting that dystrophin is important for normal retinal transmission. In the retina, dystrophin has been localized in the outer plexiform layer where dystrophin co-localizes with postsynaptic markers of photoreceptor synaptic complexes. In the present study we addressed the question of whether two major dystrophin-associated integral membrane proteins of the muscular plasma membrane, beta-dystroglycan and adhalin, are also present in photoreceptor synaptic complexes. By double immunostaining and immunoblotting we show here that beta-dystroglycan is expressed in the human retina where it co-localizes with dystrophin in photoreceptor synaptic complexes most likely on the postsynaptic side. Adhalin was not detected in the retina. Since beta-dystroglycan is a member of a transmembrane supramolecular complex thought to be important for differentiation of the neuromuscular junction, it is an attractive hypothesis that dystroglycan (linked to dystrophin) might also play a similar role in differentiation of the photoreceptor synapse. A further outcome of this study is that beta-dystroglycan is not only present in the neuromuscular junction but also associated with a well-defined synaptic complex of the central nervous system. These findings indicate a more general role of this dystrophin-associated membrane protein in synaptic functions.

Colocalization of retinal dystrophin and actin in postsynaptic dendrites of rod and cone photoreceptor synapses.

In this paper we demonstrate immunostaining specific for dystrophin in photoreceptor synapses of human, bovine and rat retinas. Cryosections of retinas incubated with dystrophin-specific monoclonal antibodies displayed a punctuate staining pattern in the outer plexiform layer. This pattern resulted from binding of the antibodies to synaptic complexes of both rods and cones, shown by double-labelling with antibodies to either synaptophysin or actin. Confocal laser fluorescence microscopy demonstrated that dystrophin staining colocalized predominantly with actin, which is concentrated in the postsynaptic portions of the synaptic complex. No significant dystrophin immunolabel was seen in the presynaptic terminals labelled with antibodies to synaptophysin, a marker of synaptic vesicles. Immunoblot analysis confirmed the presence of approximately 420 kDa and approximately 360 kDa dystrophin-like polypeptide bands associated with membranes of the bovine retina. We speculate that retinal dystrophin is involved in the linkage of actin filaments to the postsynaptic plasma membrane. Such a linkage may be important for the generation of synaptic microdomains and for certain phenomena of synaptic plasticity. The absence of dystrophin in patients suffering from Duchenne's muscular dystrophy is accompanied by visual problems and abnormalities of the electroretinogram. Therefore it is likely that retinal dystrophin plays a role in certain stages of synaptic transmission between photoreceptors and the postsynaptic dendritic complex formed by horizontal and bipolar cells.